A self-venting centrifugal pump for transporting lithium carbonate gas-liquid mixtures

Abstract

This utility model discloses a self-venting centrifugal pump for transporting lithium carbonate gas-liquid mixtures, relating to the field of fluid transport equipment technology. The aim is to achieve gas-liquid separation transport using a centrifugal pump, and the following technical solution is proposed: It includes a pump body, a first rotating shaft disposed within the pump body, a pump cover mounted on the rear side of the pump body, and a mechanical seal housing mounted on the rear side of the pump cover. An impeller is mounted on the first rotating shaft, and a second rotating shaft, coaxially arranged with the first rotating shaft, is disposed within the mechanical seal housing. A vacuum wheel is mounted on the second rotating shaft. An expansion chamber is formed at the bottom of the mechanical seal housing, and the expansion chamber is connected to the impeller chamber via the vacuum wheel chamber containing the vacuum wheel. This utility model provides an effective gas discharge path, allowing the centrifugal pump to focus on liquid transport, while the gas inside the centrifugal pump is discharged through the expansion chamber on the mechanical seal housing, thereby achieving gas-liquid separation transport in the centrifugal pump.

Description

Technical Field

[0001] This utility model relates to the field of fluid transport equipment technology, specifically to a self-venting centrifugal pump for transporting lithium carbonate gas-liquid mixed media. Background Technology

[0002] In chemical processes, gaseous media are frequently transported. For ordinary chemical centrifugal pumps, even a gas content of 1% can cause a significant drop in key performance characteristics such as pump flow rate, head, and efficiency. In some cases, gas may even accumulate in the center of the impeller, preventing discharge and causing phenomena such as air binding or drastic fluctuations in pump head. Since chemical processes require stable and reliable flow rates to ensure product quality and output, instability caused by excessively high gas content cannot guarantee the normal operation of the chemical process.

[0003] Traditional centrifugal pumps operate by utilizing the centrifugal force generated by the impeller's rotation, combined with the volute casing, to convert kinetic energy into static pressure energy. Liquids, being denser, are propelled outwards by the centrifugal force of the impeller's high-speed rotation, generating kinetic energy which is then converted into static pressure energy within the pump's volute casing. However, for gases, due to their lower density, the impeller cannot effectively expel them, causing gas to accumulate at the impeller inlet. This results in a large amount of air remaining inside the pump casing or in the suction line, preventing the formation of a sufficient low-pressure zone at the impeller center to draw liquid into the pump. Even when liquid is occasionally discharged, the entire operation is highly unstable, accompanied by a significant decrease in head, flow rate, and efficiency. Even small amounts of gas can accumulate in the low-pressure zone at the inlet, gradually amplifying the negative impact. Consequently, the gas in the gaseous medium cannot be effectively discharged from the traditional centrifugal pump, causing it to malfunction. Utility Model Content

[0004] This invention provides a self-venting centrifugal pump for conveying lithium carbonate gas-liquid mixed media, with the aim of achieving gas-liquid separation and conveying by the centrifugal pump.

[0005] The technical solution of this utility model to solve the above-mentioned technical problems is as follows:

[0006] A self-venting centrifugal pump for conveying lithium carbonate gas-liquid mixture includes a pump body, a first rotating shaft disposed within the pump body, a pump cover mounted on the rear side of the pump body, and a mechanical seal housing mounted on the rear side of the pump cover. An impeller is mounted on the first rotating shaft, and a second rotating shaft coaxially disposed within the mechanical seal housing is provided. A vacuum wheel is mounted on the second rotating shaft. An expansion chamber is formed at the bottom of the mechanical seal housing, and the expansion chamber is connected to the impeller chamber through the vacuum wheel chamber where the vacuum wheel is located.

[0007] Furthermore, the rear cover plate of the impeller has multiple through-holes, and the axis of the through-holes is parallel to the axis of the second rotating shaft.

[0008] Furthermore, an impeller nut is installed at the end of the first rotating shaft, and the impeller is fixed to the first rotating shaft by the impeller nut.

[0009] Furthermore, it also includes a connecting frame and a bearing housing. The pump body and the mechanical seal housing are both connected to the bearing housing through the connecting frame. A third rotating shaft is provided inside the bearing housing. The third rotating shaft is coaxial with the second rotating shaft. Multiple sets of bearings are provided inside the bearing housing, and all sets of bearings are fitted on the third rotating shaft.

[0010] Furthermore, an exhaust port is provided on the top of the bearing housing, and an exhaust plug is provided on the top of the exhaust port.

[0011] Furthermore, the pump body is equipped with a wear-resistant plate, which is fixed to the pump body by adjusting studs.

[0012] This utility model has the following beneficial effects:

[0013] This invention achieves efficient gas-containing transport. The centrifugal action of the vacuum wheel set on the first rotating shaft provides an effective way to discharge gas, allowing the centrifugal pump to focus on liquid transport. The gas inside the centrifugal pump is discharged through the expansion chamber set on the mechanical seal housing, thereby realizing gas-liquid separation transport of the centrifugal pump. Attached Figure Description

[0014] Figure 1 This is a cross-sectional view of the self-venting centrifugal pump for transporting lithium carbonate gas-liquid mixed media according to this utility model.

[0015] Figure 1 The reference numerals in the attached drawings are respectively: 1-pump body, 2-impeller, 21-air guide hole, 3-impeller nut, 4-wear-resistant plate, 5-pump cover, 51-mechanical seal housing, 6-bearing housing, 61-exhaust hole, 62-bearing, 7-exhaust plug, 8-connecting frame, 9-vacuum wheel, 10-adjusting stud, 11-expansion chamber, 12-vacuum wheel chamber, 13-impeller chamber, 31-first shaft, 32-second shaft, 33-third shaft. Detailed Implementation

[0016] The present invention will be further described below with reference to the accompanying drawings and embodiments:

[0017] Please refer to Figure 1This embodiment describes in detail a self-venting centrifugal pump for conveying lithium carbonate gas-liquid mixtures, including a pump body 1, a first rotating shaft 31 disposed within the pump body 1, a pump cover 5 mounted on the rear side of the pump body 1, and a mechanical seal housing 51 mounted on the rear side of the pump cover 5. An impeller 2 is mounted on the first rotating shaft 31. A second rotating shaft 32, coaxially arranged with the first rotating shaft 31, is disposed within the mechanical seal housing 51. A vacuum wheel 9 is mounted on the second rotating shaft 32. An expansion chamber 11 is formed at the bottom of the mechanical seal housing 51, and the expansion chamber 11 is connected to the impeller chamber 13 containing the impeller 2 through a vacuum wheel chamber 12 containing the vacuum wheel 9. The pump body 1 constitutes the core hydraulic chamber of the pump and is made of high-strength corrosion-resistant materials such as duplex stainless steel. The impeller chamber 13, which accommodates the impeller 2, is formed inside the pump body 1 and has an axial suction port and a tangential discharge port. The pump cover 5 is connected to the pump body 1 by flange bolts, and a metal gasket is provided for sealing the mating surface. The pump cover 5 has a vacuum wheel chamber 12 inside, and a vacuum wheel 9 is mounted on the front end of the second rotating shaft 32. Both the impeller 2 and the vacuum wheel 9 have a semi-open structure, and the vacuum wheel 9 is fixed to the second rotating shaft 32 by a key connection. The bottom of the pump cover 5 has an expansion chamber 11. Gas inside the pump body 1 is discharged to the outside of the centrifugal pump through a pipeline connected to the expansion chamber 11. The bottom of the expansion chamber 11 is connected to the suction area of ​​the vacuum wheel chamber 12 through a connecting port. The vacuum wheel chamber 12 is connected to the impeller chamber 13 through a connecting port, forming a continuous gas channel. In this embodiment, the front side refers to the fluid inlet side of the centrifugal pump, and the rear side refers to the side away from the fluid inlet of the centrifugal pump.

[0018] The motor drives the first shaft 31 and the second shaft 32 to rotate, thereby driving the impeller 2 and the vacuum wheel 9 to rotate at high speed. The rotation of the impeller 2 does work on the gas-liquid mixture entering from the suction port, and the pressurized liquid medium is discharged from the outlet of the pump body 1. During this process, some gas will accumulate near the impeller 2. Due to the opening of the vacuum wheel chamber 12, the gas that originally accumulated on the inlet side of the impeller 2 is transferred to the rear side of the impeller 2. Under the local negative pressure generated by the high-speed rotation of the vacuum wheel 9, the gas is drawn into the vacuum wheel chamber 12. The gas carrying a small amount of liquid enters the expansion chamber 11 located at the bottom of the mechanical seal housing 51 through the vacuum wheel chamber 12 and the sealed chamber in the mechanical seal housing 51. In the expansion chamber 11, the gas flow channel expands and the flow velocity decreases, causing the entrained liquid droplets to separate due to gravity settling or impacting the cavity wall. The separated liquid can flow back to the lower cavity of the mechanical seal housing 51 along the cavity wall, and the separated gas is discharged from the expansion chamber 11. The expansion chamber 11 is connected to the storage tank of the centrifugal pump through an external pipe, so that a small portion of the liquid discharged with the gas can be recycled.

[0019] The rear cover plate of impeller 2 has multiple through-holes 21, with the axis of the through-holes 21 parallel to the axis of the second rotating shaft 32. To balance the liquid pressure difference between the front and rear of impeller 2, and to allow gas accumulated at the inlet side of impeller 2 to be actively drawn out under the pressure difference, 12-18 micro-holes 21 are provided on the rear cover plate of impeller 2. The through-holes 21 allow gas to penetrate to the rear side of impeller 2 and be evenly distributed in the hub area. The through-holes 21 can improve the hydrodynamic characteristics of impeller 2 to a certain extent, increasing pump efficiency. Impeller 2 is fixedly mounted at the front end of the first rotating shaft 31 and is integrally cast from stainless steel. The axis of the through-holes 21 is parallel to the axis of the first rotating shaft 31, balancing the pressure before and after impeller 2, reducing axial thrust, and allowing some gas to be discharged from the through-holes 21. The impeller 2 rotates and does work on the gas-liquid mixture entering from the suction port, converting mechanical energy into the kinetic and pressure energy of the medium. The gas accumulated on the inlet side of the impeller 2 is drawn into the rear side of the impeller 2 through the air guide hole 21 opened on the rear cover plate of the impeller 2 under the action of the local negative pressure (suction force) generated by the high-speed rotation of the vacuum wheel 9, and gradually enters the vacuum wheel chamber 12.

[0020] An impeller nut 3 is installed at the end of the first rotating shaft 31, and the impeller 2 is fixed to the first rotating shaft 31 by the impeller nut 3. To ensure a secure installation of the impeller 2, the impeller nut 3 is used to lock the impeller 2 onto the first rotating shaft 31, and the impeller nut 3 is threadedly connected to the first rotating shaft 31. The impeller 2 is fitted onto the journal of the first rotating shaft 31 through the center hole of the hub, and is pressed and fixed by the impeller nut 3 installed at the front end of the first rotating shaft 31. The impeller nut 3 adopts a hexagonal nut structure with a nylon locking ring.

[0021] This embodiment also includes a connecting frame 8 and a bearing housing 6. The pump body 1 and the mechanical seal housing 51 are both connected to the bearing housing 6 via the connecting frame 8. A third rotating shaft 33 is located inside the bearing housing 6, connecting to a second rotating shaft 32. Multiple sets of bearings 62 are installed inside the bearing housing 6, all mounted on the third rotating shaft 33. The bearing housing 6 is a cast iron structure and is connected to the flanges of the mechanical seal housing 51 and the pump body 1 via the connecting frame 8. Flange connection surfaces are provided at both ends of the connecting frame 8. Three sets of bearings 62 are installed inside the bearing housing 6 to support the third rotating shaft 33: cylindrical roller bearings are arranged near the pump end to bear radial force; angular contact ball bearings are arranged in pairs near the drive end to bear bidirectional axial force. The bearings 62 are grease-lubricated, and the housing is filled with lithium-based grease.

[0022] A vent hole 61 is provided on the top of the bearing housing 6, and a vent plug 7 is provided on the top of the vent hole 61. In order to allow the gas inside the bearing housing 6 to be discharged in a timely manner and to prevent the gas pressure inside the bearing housing 6 from being too high, a vent hole 61 is provided at the highest point of the top of the bearing housing 6, and a stainless steel vent plug 7 is installed at the outer port of the vent hole 61. When it is necessary to discharge gas, the vent plug 7 is opened to discharge the gas.

[0023] The pump body 1 has a wear-resistant plate 4 on its inner wall, which is fixed to the pump body 1 by adjusting studs 10. The wear-resistant plate 4, made of highly wear-resistant materials such as tungsten carbide hard alloy, is fixedly installed in the easily worn areas of the pump body 1's inner wall. The wear-resistant plate 4 is adjustablely fixed to the inner wall of the pump body 1 by multiple adjusting studs 10. The adjusting studs 10 pass through through holes in the outer wall of the pump body 1 and are threaded to the wear-resistant plate 4. Tightening the adjusting studs 10 allows for precise control of the operating clearance between the wear-resistant plate 4 and the impeller 2 end face. Simultaneously, a sealing ring is used to seal the adjusting studs 10 and the pump body 1.

[0024] The shaft system comprises three coaxial shafts: the first shaft 31 mounts the impeller 2 and extends into the mechanical seal housing 51; the front end of the second shaft 32 is located inside the mechanical seal housing 51; and the third shaft 33 is located inside the bearing housing 6. The first shaft 31 and the second shaft 32 are rigidly connected by a diaphragm coupling, and the second shaft 32 and the third shaft 33 are connected by a sleeve clamp coupling to ensure coaxiality and torque transmission. The drive end of the third shaft 33 is connected to a drive motor via a flexible coupling.

[0025] A double-end mechanical seal is installed at the junction of the first shaft 31 and the second shaft 32 between the pump body 1 and the mechanical seal housing 51. The sealing cavity is connected to an external flushing system for continuous injection of cleaning buffer. Oil seals are installed at the junctions of the shafts at both ends of the bearing housing 6 to prevent grease leakage.

[0026] Self-venting operation process: After the pump starts, the motor drives the third shaft 33 to rotate, which in turn drives the second shaft 32 and the first shaft 31 to rotate synchronously through the coupling, thereby driving the impeller 2 and the vacuum wheel 9 to rotate at high speed. The rotation of the impeller 2 does work on the gas-liquid mixture entering from the suction port, converting mechanical energy into the kinetic and pressure energy of the medium. The pressurized medium is discharged from the discharge port. During this process, some gas will accumulate on the inlet side of the impeller 2. Because the centrifugal pump has a vacuum wheel chamber 12, the gas that originally accumulated on the inlet side of the impeller 2 is transferred to the rear side of the impeller 2 more quickly through the air guide hole 21 opened on the rear cover plate of the impeller 2. The gas accumulated on the rear side of the impeller 2 is drawn into the vacuum wheel chamber 12 under the local negative pressure generated by the high-speed rotation of the vacuum wheel 9. Subsequently, the gas carrying a small amount of liquid droplets enters the expansion chamber 11 located at the bottom of the mechanical seal housing 51 through the sealed chamber of the mechanical seal housing 51. Inside the expansion chamber 11, the gas flow channel suddenly expands and the flow velocity decreases significantly, causing the entrained droplets to separate due to gravity settling or impacting the chamber wall. The separated liquid can flow back along the chamber wall to the lower chamber of the mechanical seal housing 51, and the separated gas is discharged from the expansion chamber 11.

[0027] Although embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the present invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A self-venting centrifugal pump for conveying lithium carbonate gas-liquid mixture, comprising a pump body (1), a first rotating shaft (31) disposed within the pump body (1), a pump cover (5) mounted on the rear side of the pump body (1), and a mechanical seal housing (51) mounted on the rear side of the pump cover (5), wherein an impeller (2) is sleeved on the first rotating shaft (31), and a second rotating shaft (32) coaxially disposed with the first rotating shaft (31) is provided inside the mechanical seal housing (51), characterized in that, A vacuum wheel (9) is fitted on the second rotating shaft (32), and an expansion cavity (11) is opened at the bottom of the mechanical seal box (51). The expansion cavity (11) is connected to the impeller cavity (13) where the impeller (2) is located through the vacuum wheel cavity (12) where the vacuum wheel (9) is located.

2. The self-venting centrifugal pump for lithium carbonate gas-liquid hybrid medium delivery of claim 1, wherein, The impeller (2) has a plurality of through air guide holes (21) on its rear cover plate, and the axis of the air guide holes (21) is parallel to the axis of the second rotating shaft (32).

3. The self-venting centrifugal pump for lithium carbonate gas-liquid hybrid medium delivery of claim 1, wherein, An impeller nut (3) is installed at the end of the first rotating shaft (31), and the impeller (2) is fixed on the first rotating shaft (31) by the impeller nut (3).

4. The self-venting centrifugal pump for lithium carbonate gas-liquid hybrid medium delivery of claim 1, wherein, It also includes a connecting frame (8) and a bearing housing (6). The pump body (1) and the mechanical seal housing (51) are both connected to the bearing housing (6) through the connecting frame (8). The bearing housing (6) is provided with a third rotating shaft (33). The third rotating shaft (33) is coaxially arranged with the second rotating shaft (32). The bearing housing (6) is provided with multiple sets of bearings (62). The multiple sets of bearings (62) are all sleeved on the third rotating shaft (33).

5. The self-venting centrifugal pump for lithium carbonate gas-liquid hybrid medium delivery of claim 4, wherein, The bearing housing (6) has an exhaust hole (61) on its top, and an exhaust plug (7) is provided on the top of the exhaust hole (61).

6. The self-venting centrifugal pump for lithium carbonate gas-liquid mixture medium delivery according to any one of claims 1 to 5, characterized in that, The pump body (1) has a wear-resistant plate (4) on its inner wall, and the wear-resistant plate (4) is fixed to the pump body (1) by adjusting studs (10).

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